Pump structure



J. F. HOFFER PUMP STRUCTURE June 12, 1951 2 Sheets-Sheet 1 OriginalFiled Feb. 9, 1942 W im June l2, 1951 J, F, HOF-FER 2,556,426

' PUMP STRUCTURE 2 Sheets-Sheet 2 Original Filed Feb. 9, 1942 PatentedJune 12, 1951 PUMP STRUCTURE James F. Hoifer, Detroit, Mich., assignerto Ex- Cell.-O Corporation, Detroit, Mich., a corpora? tion of'Michigan.

Original application February 9, 1942, Serial No.

429,998. Divided and this. application December 1, 1944, SerialNo.566,066

The present invention relates to improvements in pumps and hasparticular reference to a new and improved pump structure which isespecially suited for supplying fuel in metered charges at a relativelyhigh pressure to. an internal combustion engine.

One of the objects of the invention is to provide a novel pump structurecomprising a high pressure delivery pump, a low pressureprimary pump forsupplying fuel to the delivery pump, and auxiliary pump means forremoving fuel and lubricant leaking from said delivery pump.

Another object is to provide a new and improved pump structure of theforegoing character in which the fuel and lubricant leaking from thedelivery pump are not intermingled.

A further object is to provide a novel primary pump having an inletpassageY connected to an enlarged surge chamber or accumulator withinthe pump body.

Another object is to provide a new and improved transfer pump unitcomprising`r a primary pump for transferring fuel to a delivery pump andhaving a pressure controlled plunger, which plunger serves also as. thepumping element of an auxiliary pumpv for removing fuel leaking from thedelivery pump.

.A further object is to provide a novel pump unit comprising a primarypump for transferring fuel to a delivery pump and having a reciprocatorypiston which serves.. alsov as the piston of an auxiliary pump forremoving lubricant leaking from the delivery pump.

Still another object is to provide a new and improved pump structureincluding a delivery pump and a primary pump for supplying fuel to thedelivery pump, said pumps having a novel drive connection for effectingsynchronous operation.

Further objects and advantages will become apparent as the descriptionproceeds.

lin the accompanying. drawings,

Figure l is a fragmentary verticalV sectional view of a pump structureembodying the features of my invention, part of the structure beingshown in side elevation.

Fig. 2 is a top plan View of a transfer pump unit forming part of thestructure.

Fig. 3 is a side elevation of the transfer pump unit.

Fig. l is a left-end elevation.

Fig. 5 is a right-end elevation.

Fig. 6 is a transverse vertical sectional view taken along line S--GofFig. l.

Fig. '7 is a fragmentary detail sectional view taken along line 7.-1 ofFig. 6.

12 Claims. (Cl. 1'03-5) Fig. 8 is an enlarged sectional view through avalve forming part of the transfer pump unit.

Fig. 9 is a fragmentary sectional view taken along line 9 9 of Fig. 6.

Referring more particularly to the drawings, the pump structure,illustrating the invention, comprises generally a delivery pump I fordischarging fluid under a relatively high pressure, and a transfer pumpunit, including a primary pump 2 for supplying or transferring fluidunder a relatively low pressure to the inlet of the delivery pump I, andtwo auxiliary pumps 3 and 4 respectively for scavenging accumulatedfluid leaking from the pumping means of the delivery pump, andaccumulated lubricant leaking from or circulating through the drivingmechanism of the delivery pump. The pumps 2', 3 and 4 are combined in aunit assembly, and are operated in timed relation to each other and tothe delivery pump I'.

The high pressure delivery pump I may be of any desired form or type,and is herein disclosed for purposes of illustration as an adjustablemetering and distributing fuel pump like that disclosed in my Patent No.2,265,232, issued December 9, 1941. In the present instance, the fueldelivery pump I comprises a housing 5 adapted to be mounted on asuitable support, such as the crank case of an internal combustionengine. A cylinder body 6 is mounted in one end of the housing 5, and isformed with a central bore lv and with a plurality of parallel pumpcylinders 8 arranged in angularly spaced relation about the bore. Aplurality of pump pistons 9 are reciprocably disposed in the cylinders8, and are urged outwardly by compression springs Ill. Mounted in theother end of the housing 5 is a driving mechanism for effectingreclprocation of the pistons 9 in uniformly timed sequence. Thismechanism comprises a plurality of actuating plungers or tappets I Ireciprocably guided in the' housing 5, and disposed in axial alinement,and in end abutting engagement, respectively with the pistons 9. Arotary swash plate I2 ccacts with the plungers II, and is operable by acentral drive shaft I3 in axial alinement with the bore I. The pressureends of the pump cylinders 8 open respectively through outlet checkvalves III to a plurality of delivery lines I5, and have individualinlet ports IS opening in a common transverse plane from the bore 'I. Agroove II is formed in the periphery of the bore l, and is open to aninlet passage I8 connected to a low pressure fluid supply line I9.Mounted in the bore 'l is a rotary valve member 20 having a relief' area2l adapted to effect communication between the ports I and the grooveI1, and having a narrow land area 22 movable successively across theports to close each port during a predetermined portion of the workingstroke of the associated piston 9. The valve member 2Q is operativelyconnected to the shaft I3 for rotation thereby in timed relation to thereciprocation of the pistons 3.

In the operation of the delivery pump I, predetermined quantities ofuid, such as liquid fuel, are discharged under a relatively highpressure and in timed sequence to the delivery lines I5. Any fuelleaking from the closed ends of the cylinders Z along the pistons 9,.and from the groove i? inwardly along the valve member 2G, will passinto the left-end portion of the interior of the housing 5 between thecylinder body 5 and the pump driving mechanism. Similarly, any lubricantleaking inwardly along the plungers II will pass into the right-endportion of the interior of the' housing 5 between the cylinder body 5and the driving mechanism.

The transfer pump unit comprises a generally rectangular body 23 whichis normally disposed in a horizontal position, and which is formed atthe top with a flat marginal flange or plate 25 adapted to be secured inposition against a mounting surface 25 on the underside of the deliverypump housing 5. Preferably, the plate 2li is located by a plurality ofdiagonally spaced dowel pins 2e and is secured to the housing 5 by fourcorner bolts 2l. A marginal gasket 2 is inserted between the housing 5and the plate 24 to obtain a duid-tight connection.

The bottom wall of the pump housing intermediate the pumping unit andthe drive mechanism, is formed with an opening 29 which is circumscribedby the marginal surface 25, and which hence is closed by the plate 25 ofthe to form two open reservoirs or sumps 3B and 3! which are arrangedrespectively to collect fuel and lubricant leaking from the pumping unitand the drive mechanism into the housing 5 and then dripping or drainingthrough the opening 29. A transverse rib or dam 32, rising to the toplevel of the plate 2li, separates the sumps 3Q and 3l to preventintermingling of the leakage fuel and lubricant. The fluids collectingin the sumps and 3i are removed by the auxiliary pumps 3 and l as ishereinafter more fully described.

The primary pump 2, for transferring fuel to the supply line I9 of thepump I, comprises a longitudinal medial cylinder 33 formed in andopening through the body 23. One end of the cylinder is closed by a plug3d, and the other end is formed with a counterbore 35 constituting anauxiliary cylinder and defining an outwardly facing annular stopshoulder 35. A sleeve nut 37 is threaded into the outer end of thecounterbore 35 to close the latter.

Opening respectively to opposite sides of the cylinder 33 in a commontransverse plane intermediate its ends are an inlet port 38 and anoutlet port 39. The inlet port 38 is connected through an inlet checkvalve G9 with a supply passage il which extends to one end of the body23. A suction line l2 leading from a suitable source of fuel, such as asupply tank (not shown) is detachably connected to the cody 23 andcommunicates with the outer end of the passage 4I.

The inlet check valve comprises a valve passage intersecting the supplypassage 4I and opening vertically through a. valve seat 54 to aactuating plunger or tappet II. body 23. The top face of the plate 24 isrecessed 4 valve chamber d5. The chamber is closed at the top by a screwplug A5, and connects with the port 39. A suitable valve member 41 isslidably guided in the plug 45, and is normally urged by a compressionspring 48 into engagement with the seat 4d.

Formed in the body 23 and connected to the inner end of the supplypassage 4I is a large bore-49 which serves as a surge chamber oraccumulator. The outer end of the bore 49 is closed by a plug 55, andthe two plugs 34 and 5E! are secured in position by a lock screw 5 I.

The outlet port 39 is connected through an outlet check valve 52 to adelivery passage 53 which extends to one end of the body 23, and isconnected with the supply line I3 leading to the inlet of the pump I.The outlet check valve 52 comprises a valve chamber 54 'formed in oneside of the body 23, and closed by a screw plug 55. The chamber 54 opensthrough a valve seat 56 to the outlet port 39, and intersects thedelivery passage 53. A suitable valve member 51, slidably guided in thescrew plug 55, is normally urged into engagement with the seat 53 by acoiled compression spring 58.

A relief valve 53 is connected to the chamber 54 to dissipate excessivepressures in the event of abnormal operating conditions. The valve 59has an inlet passage 69 controlled by an adjustable spring-seated ballvalve member 6I and has an outlet passage 62 opening to the sump 39.

Reciprocably mounted in the cylinder 33 intermediate its ends is a pumppiston I63. Preferably, the piston 63 is driven by the delivery pump Iin timed relation to the pistons 9. The drive connection comprises avertical pin 54 which is formed at the upper end with a sleeve 65fitting snugly about and rigidly locked to the lowermost The lower endof the pin 5ft extends with a close t into a diametrical bore 65 in thepiston 63 substantially midway of its ends. vA relatively large verticalbore 6'! in the body 23 opens downwardly from the sump 35, and fullyintersects the cylinder 33 to permit the drive connection and toaccommodate the translation of the pin 54. The bore 6'! is somewhatlarger in diameter than the cylinder 33, and hence provides verticalpassages 58 at opposite sides of the piston 33 adapted to receive fuelfrom the sump 39.

One end of the piston 63, having an end face 59, constitutes the activeend in the primary pump 2. At the end of the pressure stroke, the pistonface 39 advances substantially to the plane of the inlet and outletports 38 and 39. To prevent blocking of these ports, suitable arcuategrooves I0 are formed in opposite sides of the piston 53 at the end face69.

In operation, movement of the piston 53 on its outward stroke away fromthe ports 38 and 39 will cause the flow of fuel from the supply tankthrough the inlet valve 40 in whatever amount is required to ll thecylinder 33, and movement of the piston in the reverse direction on thepressure stroke will cause the discharge of fuel under pressure throughthe outlet check valve 52 to the supply line I9 for the delivery pump I.

A pressure control plunger 1I is reciprocable in the left end of thecylinder 33 in opposed relation to the active end of the piston 63, andcoacts therewith to define the pressure chamber of the pump 2. Theplunger has an enlarged peripheral flange or head 'I2 freelyreciprooable in the auxiliary cylinder 35, and adapted to limit inwardmovement by engagement with the stop: 36; The plunger 1 I. isA urgedinwardly by spring pressure, and iny effect constitutes a yieldable endWall of the pump pressure chamber.. In the present instance, the springmeans comprises two coaxialv compression springs 13 and I4 which at oneend bear against a flange 1.5 on a pilot sleeve. 13 seated in the sleevenut 31., and which atl the other end engage in a centering recess 1 inthe head 12.

The displacement of the piston 63 is normally equal to and preferably inexcess of the maxi.- mum requirements ofthe associated fuel injectionpump and the. pressure control plunger Tl isoperable automatically tovary the-volume of fuel actuallyl delivered in accordance with. the.existing requirements. at a predetermined maximum pressure. If atanytime the full displacement of the piston 63 is required, the springs f3land 1.4 will maintain the head. 1.2 against the stopA 36 toy constrainthe plunger 1| against movement out of its innermost position. In. theevent that. the full displacement of the piston 63 isf not required, thepressure inv the cylinder 33' will cause the plunger 1| to moveoutwardly during the pressure stroke of the piston 63 so that onlyvpart. of the displacement of the piston will be discharged through thevalve 52. In. the subsequent suction stroke of the piston 63; theplunger 12| will. move inwardly to maintain the fuel' iin the.l cylinder33 under a. predetermined maximum discharge pressure until the head 12again engages. the stop 36, and. thereafter fuelpin an amount sui'cientto; ref-lll the cylinder will enter through the valve 40.. If no fuel isrequired by the delivery pump the plunger 1| willtravel in synchronismwith the piston '63,

thereby resulting in zerodelivery.` Consequently,

the pump 2 isv self-relieving tov supply the demands. of the deliverypump fromv zero to maximum at the maximum delivery pressure.

Thev auxiliary pump 3. utilizes the counterbore 35 as a cylinder, andthel plunger 1|? as' a piston, and is operable to take leakage fuel fromthe sump 3B and transfer it to the source. of. supply for the deliverypump or to some other convenient place.. The pump 3 hasan inlet passage1.8 which connects: at one end with the bottom ofi the bore' 61,. andwhich opens at the other end' through a. port 19` to the outer endportion of thev cylinderl 33. The piston 1-'|` serves to uncover theport 19 when in its innermost position in the cylinder 33,. and to closethe port upon initial. movement out of this position. In the presentinstance, the piston 1| is formed beneath the head 12; with a peripheralgroove 8|) adapted to communicate with the port 19v when the head 12.Vengages the stop 36,. and with a plurality of apertures 8f| opening fromthe groovev 80 through the. head 12 to complete the flow connection tothe cylinder 35.

The pumpv 3 has an outlet check valve 82 mounted in' the sleeve 16- andladapted for connection to a return line 8-3. be of any suitable form,andi in the present instance (see Fig.. 85)" comprises a body 64: havinga valve passage |35 with. a seat 86. A ball. valve member 81 is normallyurged against the seat Sift by' a coiled' compression spring 88 whichis. confined"v in the body 84 by a tubular* pilot sleeve 89;Preferablynltering elements 90 are mounted in. opposite ends of thevalve body 845.v

Inl operation, it will'V be seen that the plunger 1"|I performs the dualfunction of controlling the effective displacement. of the pump 2 atagiven maximurnpressure in accordance with the re- The valve 8.2 may'quirements of the pump I, and at the same time of serving as they pistonof. the `pump 3. Upon inward movement of the piston 1| t0 the right intoengagement with the stop 36, a suction is created in the cylinder 35,and the port 19 is opened' to admit. fuel from the sump 30. Upon outwardmovement of the piston 1|, the port '1.9 is cut off, and thereafter thefuel in the cylind'er 35 is compressed and discharged through the valve82 into the line 83 for return to the fuel supply tank. While the pump 3is operative only as. an incident. to the reciprocation of the plunger1|, the latter is reciprocated enough in. the normal operation of thepump structure to. remove: all the leakage fuel accumulating iny thepump 30.

The auxiliary pump 4, for removing lubricant leaking from the housing 5and collecting into the sump 3|, utilizes the right end of piston 63 asthe pumping element and the closed end of the cylinder 33 as thecylinder or pressure chamber.' 9|... Thus, the piston 63' is of thedouble acting. type, its pressure stroke for the pump 2 being the:suction stroke for the pump 4, and its suction stroke for the pump 2being the pressure stroke for the pump 4.

The" cylinder 9| has anl inlet port 92 which opensr from the sump 3|,and which is uncovered by the piston. 63 at the end of the suctionstroke and is closed in the initial movement of the piston on thepressure: stroke. The cylinder 9| also has an outlet passage 93 whichopens through the body 2.3: to. the top` face ofv the flange 24- inregistration with a passage 94 through the housing 5i for. returning.the discharged lubricant to the crank case of the engine. The gasket 23between the body 5- of the pump I and the mounting plate 24" of the pump2 is suitably apertured to establish communication between the passages93 andV 94; Inserted in the passage 33y is. an outlet check valve unit95 of the same type as the valve 82.

In operation, the piston 63 uncovers the inlet port 92 at the end of thesuction stroke in the cylinder 9| to permit the entry of accumulatinglubricating oil from the sump 3|. On the pressure stroke of the pump- 4,the piston 63l will dis charge-the lubricant from the cylinder 9|through the passages 93 and 94 and. valve 95 to the engine crank case.

The dam 342y prevents the fuel and lubricant collecting respectively inthe sumps 36 and 3| normally from intermingling. If either of theauxiliary pumps 3 or 4 should fail to operate properly to transfer thelfluid collecting in the corresponding sumps, the associated sump wouldnll up and the fluid therein would overow the darn 32. Means is providedfor indicating such abnormal condition of operation, and in the presentiinstance, this means comprises two longitudinal grooves 96 formed in thetop of the dam at opposite sides of the vertical bore 61, and arrangedtov catch any overflow from either sump. The grooves are connectedthrough vertical down-flow passages 91 to two relatively large bores 98formed in. opposite sides of the body 23. Suitable lters 99 are mountedin the bores 98. In theV event of any overflow, fluid will pass to thefilters 99, and indicate that at least one of the pumps 3 and 4 is notoperating properly. From'. the character of the fluid noticeable at thefilters 93, the offending pump can be identified.

Means is also provided for reciprocating the plunger 1li manually toprime the pump without.I cranking the engine when the pump is idle.

The means for this purpose comprises an actuating plunger IGI) whichextends reciprocably through a bore lill in the body 23.. One end of theplunger Iil projects for engagement with the head l2, and the other endprojects from the body 23 for engagement by the rounded free end of alever arm |02 fixed on a rock shaft W3. The latter is journaled inparallel spaced lugs or Webs i534 integral with one end of the body 23.A hand lever |85 may be nxed on the shaft 183 for actuating the latter.Normally, the springs i3 and ifi acting through the head 'l2 tend tomove the piston ll in its suction stroke, and to swing the lever It tothe right. Additional spring means may, however, be provided forinsuring movement of the lever 95 to the right independently of thepiston ll. This spring means comprises a plunger 06 reciprocable in abore lill parallel to the bore IDI in the body 23, and urged outwardlyby a coiled compression spring H33 into engagement with the lever armM32. By alternately actuating the hand lever IE5, first in one directionagainst the action of the springs 13, 'M and Hi8, and then in thereverse direction, pumping reciprocation will be imparted to the pistonll, independently of the operation of the pump 2. The piston 'il will,on its outward stroke, take in fuel through the valve 4G, and on itspressure stroke discharge fuel through the valve 52.

The present application is a division of my copending application SerialNo. 429,998, filed February 9, 1942 (now Patent No. 2,383,483).

I claim as my invention:

l. A pump structure comprising, in combination, a delivery pump having ahousing enclosing a pumping unit in one end and a driving unit in theother end, and a transfer pump unit mounted on the underside of saidhousing and constituting a closure therefor, said transfer pump unitincluding a primary pump operable in timed relation to said deliverypump and having a discharge line connected to the inlet of said pumpingunit, an auxiliary pump operable as an incident to the operation of saidprimary pump to remove to an external point from said housing fluidleaking thereto from said pumping unit, and a second auxiliary pumpoperable in synchronism With said primary pump for removing to anoutside point from said housing lubricant leaking thereto from saiddriving unit.

2. A pump structure comprising, in combination, a delivery pump having ahousing enclosing a pumping unit in one end and a driving unit in theother end, and a transfer pump unit mounted on the underside of saidhousing and constituting a closure therefor, said transfer pump unitincluding a primaiy pump operable in timed relation to said deliverypump and having a discharge line connected to the inlet of said pumpingunit, and including an auxiliary pump operable in synchronism with saidprimary pump and having a discharge line independent of said primarypump and said first mentioned discharge line for removing to an outsidepoint from said housing lubricant leaking thereto from said drivingunit.

3. A pump structure comprising, in combination, a delivery pump having ahousing enclosing a pumping unit in one end and a driving unit in theother end, and a transfer pump unit mounted on the underside of saidhousing and constituting a closure therefor, said transfer pump unitincluding a primary pump operable in timed relation to said deliverypump and hav- (Effi ing a discharge line connected to the inlet of saidpumping unit, and including an auxiliary pump operable as an incident tothe operation of said primary pump and having a discharge lineindependent of said primary pump and said first mentioned discharge lineto remove to a point external from said housing and transfer pump unitiiuid leaking thereto from said pumping unit.

4. A pump structure comprising, in combination, a delivery pump having ahousing enclosing a pumping unit in one end and a driving unit in theother end, and a transfer pump unit mounted on said housing andconstituting a closure therefor, said transfer pump unit including aprimary pump operable in timed relation to said delivery pump and havinga discharge line connected to the inlet of said pumping unit, anauxiliary pump operable in timed relation to said primary pump to removefrom said housing iluid leaking thereto from said pumping unit, and asecond auxiliary pump operable in syrichronism with said primary pumpfor removing from said housing lubricant leaking thereto from said'drive unit.

5. A pump structure comprising, in combination, a delivery pump having ahousing enclosing a pumping unit in one end and a driving unit in theother end, and a transfer pump unit mounted on said housing andconstituting a closure therefor, said transfervpump unit including aprimary pump operable in timed relation to said delivery pump and havinga discharge line connected to the inlet' of said pumping unit, anauxiliary pump operable in timed relation to said primary pump to removefrom said housing uid leaking thereto from said pumping unit, and asecond auxiliary pump operable'in synchronism With said primary pump forremovf ing from said housing lubricant leaking lthereto from said driveunit, said primary and auxiliary pumps having independent outletpassages to prevent intermingling of the uids discharged therefrom.

6. A pump structure comprising, in combination, a delivery pump having ahousing enclosing a pumping unit in one end and a driving unit in theother end, and a transfer pump unit mounted on and enclosing theunderside of said housing and formed in the top with a first sumplocated to collect fluid leaking from said pumping unit, and a secondsump located to collect lubricant leaking from said driving unit, saidtransfer pump 'unit including a primary pump for supplying fluid to theinlet of said pumping unit, an auxiliary pump for transferring fluidfrom said `first sump, and an auxiliary pump for transferring fluid fromsaid second sump.

7. A pump structure comprising, in combination, a delivery pump having ahousing enclos'- ing a pumping unit in one end and a driving unit in theother end, and a transfer pump unit mounted on and enclosing theunderside of said housing and formed in the top with a sump located tocollect fluid leaking from said pumping unit, and 9. second sumpseparated from said rst sump by a dam and located to collect lubricantleaking from said driving unit, said transfer pump unit including aprimary pump for supplying fluid to the inlet of said pumping unit, anauxiliary pump for transferring uid from said first sump separate fromthe delivery of said primary pump, and an auxiliary pump fortransferring iluid from said second sump l separate from the delivery ofsaid primary pump.

8. A pump structure comprising, in combination, a delivery pump having ahousing enclosing a pumping unit in one end and a driving unit in theother end, and a transfer pump unit mounted on and enclosing theunderside of said housing and formed in the top with a sump located tocollect uid leaking from said pumping unit, and a second sump separatedfrom said iirst sump by a dam and located to collect lubricant leakingfrom said driving unit, said transfer pump unit includ-ing a primarypump for supplying uid to the inlet of said pumping unit, an auxiliarypump for transferring fluid from said rst sump separate from thedelivery of said primary pump, and an auxiliary pump for transferringfluid from said second sump separate from the delivery of said primarypump, all of said pumps being operable in timed relation.

9. A `pump structure comprising, in combination, a delivery pump havinga housing enclosing a pumping unit in one end and a driving unit in theother end, and a transfer pump unit mounted on and enclosing theunderside of said housing and formed in the top with a sump located tocollect fluid leaking from said pumping unit, and a second sumpseparated from said :trst sump by a dam and located to collect lubricantleaking from said driving unit, said transfer pump unit including aprimary pump for supplying uid to the inlet of said pumping unit, anauxiliary pump for transferring fluid from said rst sump separate fromthe delivery of said primary pump, and an auxiliary pump fortransferring fluid from said second sump separate from the delivery ofsaid primary pump, and means for indicating the overflow of fluid fromeither sump across said dam.

10. A pump structure comprising, in combination, a delivery pump havinga housing enclosing a pumping unit, and a transfer pump unit mounted onand enclosing the underside of said housing and formed in the top With asump 1ocated to collect fluid leaking from said pumping unit, saidtransfer pump unit including a primary pump for supplying fluid to theinlet of said pumping unit, and an auxiliary pump having an inlet opento said sump and a discharge line leading directly from said auxiliarypump independently of said primary pump for .transferring uid fromsaid'sump separate from the delivery of said primary pump.

11. A pump structure comprising, in combination, a delivery pump havinga housing enclosing a pumping unit, and a transfer pump unit mounted onand enclosing the underside of said housing and formed in the top w-itha sump having a dam and located to collect iluid leaking from saidpumping unit, said transfer pump unit including a primary pump forsupplying fluid to the inlet of said pumping unit, and an auxiliary pumpfor transferring uid from said sump separate from the delivery of saidprimary pump, and means for indicating the overflow of .fluid from saidsump across said dam.

12. A pump structure comprising, in combination, a fuel delivery pumphaving a plurality of reciprocatory pump pistons reciprocable in timedsequence to deliver metered charges of fuel, a plurality ofreciprocatory tappets for operating said pistons, and means forreciprocating said tappets, and a primary pump having a cylinder bodymounted on said delivery pump and formed with an opening in the topcommunicating with the interior of said delivery pump, a pistonreciprocable in said cylinder body and having a diametrical boreintermediate its ends, a drive pin rigidly anchored at one end to one ofsaid tappets for movement therewith and extending transversely therefromthrough said opening into said diametrical bore to establish a driveconnection for said piston, and means for supplying fuel to saidcylinder body during the suction stroke of said piston and dischargingfuel from said cylinder body to the inlet of said delivery pump duringthe pressure stroke of said piston.

JAMES F. HOFFER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,535,643 Astrom Apr. 28, 19252,093,003 Bowman Sept. 14, 1937 2,160,735 Hoffer May 30, 1939 2,214,257Pfauser Sept. 10, 1940 2,265,232 Hoffer Dec. 9, 1941 2,310,370 HoiferFeb. 9, 1943 2,331,462 Denigan Oct. 12, 1943 2,383,483 Hoiler Aug. 28,1945

